The present invention relates generally to bicycles and, more particularly, to an adjustable bicycle seat or saddle assembly that includes a bifurcated nose portion. Alternate respective halves of the nose portion can be moved in an inward or outward lateral direction with respect to a longitudinal axis of the seat assembly to attain a desired interaction with the adjacent anatomy of an individual rider.
Many bicycle riders experience discomfort attributable to even moderate durations spent seated upon a bicycle seat. The multitude of bicycle seats on the market attests to the wide range of rider preferences and suggests that the final solution has yet to be found. Seat comfort depends on many factors, among them, the compliance or firmness of the padding, the appropriate seating surface shape, rider anatomy, compliance and/or responsiveness to rider motion associated with pedal operation, and even individual rider preference.
The thickness of padding along with the density or firmness of the padding also has an effect on comfort. Generally, increased pressure between the rider's body and the seat results in increased discomfort for the rider. The opposite is also true: decreasing pressure generally results in decreased discomfort. In an effort to reduce pressure, some seat designs have targeted specific areas of the rider's body that are less able to withstand pressures by completely removing material from the seating surface (cutout seats), thus eliminating pressure at that spot. However, such seats invariably must increase the pressure elsewhere on the body because the same portion of the rider's body weight is now supported over a decreased surface area, thus increasing the pressure on the parts of the body that remain in contact with the remaining surface of the seat and are more able to tolerate such increased loading.
Yet another source of seat discomfort that is unaccounted for in many seat designs is the natural movement of the rider. All riders' pelvises move during pedaling, and seats need to be designed to accommodate, not oppose, such natural pelvis movement. For example, during the study of the three dimensional movements of over two dozen men and women, it was found that during each pedal stroke, the pelvis moves so that the hip joint translates (on average) roughly 10 millimeters forward and roughly 10 millimeters downward with each downstroke of the pedal. This movement was generally unaffected by changing the rider's power output or the seat's rear view curvature or compliance and is therefore considered to be a natural movement. This movement can also be described as a twisting (about a vertical axis) and rolling (about a longitudinal axis) of the riders' pelvis. This natural movement of the pelvis may contribute to discomfort through a shearing or scrubbing stress between the rider and the seat surface, and through a cyclic increase and decrease of the pressure between the rider's leg and the top surface and outer edges of the seat.
Another source of discomfort on some bicycle seats is that skeletal dimensions differ from one individual to the next. A rider whose pelvic dimensions are mis-matched to the seat's dimensions can experience discomfort as a result. For example, it can be uncomfortable for a rider with narrow pelvic dimensions to sit on a wider seat, since the extra width of the seat may interfere with the rider's natural pedaling motion by, for example, the rider's legs pushing on the sides of the seat. This pushing can cause intermittent pressure with each pedal stroke as well as chafing of the skin as the leg rubs across such an unyielding seat surface.
Likewise, it may be uncomfortable for a rider with wider pelvic dimensions to sit on a narrow seat, since the sit bones are then supported more medially on the ischiopubic rami, at a sloped angle that increases the lateral force component of the rider's body weight on the seat. This lateral force component, though helpful in controlling lateral movement and stability of the bicycle, can, if it grows too large, lead to excessive pressure on the rider's body at these contact points resulting in rider discomfort.
In some cases, when the rider's pelvic width is much larger than the seat's width, the sit bones may be completely off the edges of the seat. Such an association can cause an even greater increase in pressure and discomfort on the inner edges of the ischiopubic rami, can greatly increase the pressure along the center of the seat's length and therefore on the rider's corresponding perineum or perineal region, and therefore lead to even greater rider discomfort.
Yet another influence on seat discomfort is the ability of the seat to comfortably accommodate the genital area of the rider. Pressure on the genitals or perineum of the rider can be uncomfortable due to the nerves in this area and/or because the flesh there is seldom sat upon, is generally highly sensitive, has limited musculature, and is frequently less toughened than adjacent areas of the anatomy. Discomfort associated with pressure in this area is especially evident in individuals who are not accustomed to sitting on a bicycle seat. The increased pressure on the left and right side contact points of the ischiopubic rami can also lead to increased rider discomfort. This discomfort is sometimes described as a “splitting effect.” Others have attempted to provide a more comfortable saddle but such seats are commonly provided as a fixed shape saddle. Many such seats include a generally elongated longitudinal recess, groove, or channel that is shaped to accommodate the genital area and/or limit contact with the rider genitals and/or perineum. Unfortunately, each fixed shape seat assembly has a very limited field of consumers or users such that large scale manufacturing of such seat assemblies is generally unfeasible.
Therefore, there is a need for a bicycle seat system that accommodates the genitals or perineum of the rider, provides a desired lateral stiffness to allow desired lateral interaction with the seat, and can satisfy the individual preferences of more than one class, gender, or physical shape of a user. The present invention discloses such a bicycle seat system.